Flexible, Efficient Thermoelectric Generators to Power Next-Gen Wearable Devices
How to supply power in a stable and reliable manner is one of the most critical issues to commercialize wearable devices.
A team of KAIST researchers [have developed] a glass fabric-based thermoelectric (TE) generator that is extremely light and flexible and produces electricity from the heat of the human body. In fact, it is so flexible that the allowable bending radius of the generator is as low as 20 mm. There are no changes in performance even if the generator bends upward and downward for up to 120 cycles.
To date, two types of TE generators have been developed based either on organic or inorganic materials. The organic-based TE generators use polymers that are highly flexible and compatible with human skin, ideal for wearable electronics. The polymers, however, have a low power output. Inorganic-based TE generators produce a high electrical energy, but they are heavy, rigid, and bulky.
Professor Cho came up with a new concept and design technique to build a flexible TE generator that minimizes thermal energy loss but maximizes power output. His team synthesized liquid-like pastes of n-type (Bi2Te3) and p-type (Sb2Te3) TE materials and printed them onto a glass fabric by applying a screen printing technique. The pastes permeated through the meshes of the fabric and formed films of TE materials in a range of thickness of several hundreds of microns. As a result, hundreds of TE material dots (in combination of n and p types) were printed and well arranged on a specific area of the glass fabric.
Ketamine, an anesthetic sometimes abused as a street drug, increases the synaptic connections between brain cells and in low doses acts as a powerful antidepressant, Yale researchers have found. However, stress has the opposite effect, shrinking the number of synaptic spines, triggering depression.
In the April 13 online issue of the journal Nature Medicine, Yale researchers found that expression of single gene called REDD1 enables stress to damage brain cells and cause depressive behavior.
“We found if we delete REDD1, we can block the effects of stress in mice,” said Ron Duman, the Elizabeth Mears and House Jameson Professor of Psychiatry and professor of neurobiology.
In recent studies, the Yale team showed that ketamine activates the mTORC1 pathway, which in turn spurs synthesis of synaptic proteins and connections. In the new study, they show that the REDD1 gene expression blocks mTORC1 activity and decreases the number of synaptic connections. The new study by Duman and lead author Kristie Ota showed that mice without the REDD1 gene were impervious to the synaptic and behavioral deficits caused by stress. By contrast, when the gene was over-expressed, mice exhibited loss of synaptic connections and increased depression and anxiety behaviors.
In addition, post-mortem examinations of people who had suffered from depression showed high levels of REDD1 in cortical regions associated with depression.
Yale’s work with ketamine has already led to development of new classes of antidepressants, which are currently in clinical trials. Duman said these new findings may provide a new drug target that directly blunts the negative impacts of stress.
“ After all, if we already have a physics simulator in our heads, why did scientists have to discover the laws of physics, and why do we have to learn physics in school (or not at all)? Part of the answer may lie in the distinction between implicit and explicit knowledge. A bird doesn’t have to be able to teach a university course on aerodynamics in order to fly, and we don’t have to understand biophysics in order to walk or neuroscience in order to think. ”
“ You don’t understand an antagonist until you understand why he’s a protagonist in his own version of the world. ”
John Rogers (via psych-facts)
This GIF shows an example of conductive ink.
Circuit Scribe is a rollerball pen that uses a silver conductive ink to let you create fully functioning circuits as fast as you can can draw, making it cheaper, faster, and easier to test out electronics and prototype concepts.
Section of the Monkey Head Nebula, also known as NGC 2174. ‘The Great Wave’ See comments for article, celebrating 24years of the Hubble telescope.
“ Relativity applies to physics, not ethics. ”
Albert Einstein. (via quotedojo)
NGC 2683: Edge-On Spiral Galaxy